Skip to main content
Search type Search syntax
Tags [tag]
Exact "words here"
Author user:1234
user:me (yours)
Score score:3 (3+)
score:0 (none)
Answers answers:3 (3+)
answers:0 (none)
isaccepted:yes
hasaccepted:no
inquestion:1234
Views views:250
Code code:"if (foo != bar)"
Sections title:apples
body:"apples oranges"
URL url:"*.example.com"
Saves in:saves
Status closed:yes
duplicate:no
migrated:no
wiki:no
Types is:question
is:answer
Exclude -[tag]
-apples
For more details on advanced search visit our help page
Results tagged with
Search options not deleted user 16537
2 votes

Conjecture about commutative semigroups

As a complement to my previous non-answer, let me show that the OP's conjecture holds for any order-$3$ commutative semigroup $S$ that is not a group (equivalently, that is not a cyclic group of order …
Salvo Tringali's user avatar
4 votes

Conjecture about commutative semigroups

This is not an answer, but it's too long for a comment: I'm going to show that the OP's conjecture is true in some (admittedly, rather special) cases. It is hoped that this will help to find a counter …
Salvo Tringali's user avatar